Fluid filtration systems are an important component of motor vehicles and the like because of the tight design tolerances required by modern engines. No matter how carefully fuel is handled, contaminants find their way into fuel during transfer, storage, or even inside vehicle tanks. Contaminated fuel can cause damage to fuel pumps, fuel injectors, pistons, valves and so forth. One concept of the present invention is preventing fuel delivery to the engine if a proper filter cartridge is not installed on a centerpost assembly. If a proper filter cartridge is not installed, fuel is prevented from being supplied to the engine and therefore the engine will not run.